Hello everyone,
I need your advice: We contractually agreed with our main contractor that the Wolf gas-solar unit CSZ-2-14/300R would be installed in our house. This week, I accidentally discovered that instead, the next larger model, the CSZ-2-20/300R, has been installed. (The house is not finished yet; handover is expected in March.)
As the model names suggest, these units have maximum outputs of 14 kW and 20 kW, respectively. If I understand our energy saving certificate correctly, our house (energy saving regulations, 225 m² (2420 ft²)) has an annual heat demand of 14,987 kWh (11,681 kWh space heating, 3,306 kWh domestic hot water). Lacking technical expertise, I found during some initial research that I can estimate the heating load by dividing annual heating hours (about 2,100 h?) into this. Using this rough calculation, I arrive at a heating load of around 7.1 kW. Is this correct so far, and am I right to assume that this means the 20 kW version is significantly oversized?
Another problem is that the lower modulation limit of the larger boiler is much higher: 4.4 kW compared to 2.1 kW. I’m concerned that especially during transitional seasons, the boiler will cycle more frequently, leading to faster wear and less efficiency overall.
I haven’t been able to speak directly with the installer yet. The construction manager of the main contractor relayed the installer’s explanation that the unit was “sized larger due to the building size.”
I will discuss this with our independent construction expert next week.
So here are my questions:
Is my assumption correct that the 20 kW version is completely oversized?
Is my assumption correct that the higher lower modulation limit is a disadvantage for us?
How would you approach this situation? How serious do you see the issue, and what options do I have?
Thanks for your help
I need your advice: We contractually agreed with our main contractor that the Wolf gas-solar unit CSZ-2-14/300R would be installed in our house. This week, I accidentally discovered that instead, the next larger model, the CSZ-2-20/300R, has been installed. (The house is not finished yet; handover is expected in March.)
As the model names suggest, these units have maximum outputs of 14 kW and 20 kW, respectively. If I understand our energy saving certificate correctly, our house (energy saving regulations, 225 m² (2420 ft²)) has an annual heat demand of 14,987 kWh (11,681 kWh space heating, 3,306 kWh domestic hot water). Lacking technical expertise, I found during some initial research that I can estimate the heating load by dividing annual heating hours (about 2,100 h?) into this. Using this rough calculation, I arrive at a heating load of around 7.1 kW. Is this correct so far, and am I right to assume that this means the 20 kW version is significantly oversized?
Another problem is that the lower modulation limit of the larger boiler is much higher: 4.4 kW compared to 2.1 kW. I’m concerned that especially during transitional seasons, the boiler will cycle more frequently, leading to faster wear and less efficiency overall.
I haven’t been able to speak directly with the installer yet. The construction manager of the main contractor relayed the installer’s explanation that the unit was “sized larger due to the building size.”
I will discuss this with our independent construction expert next week.
So here are my questions:
Is my assumption correct that the 20 kW version is completely oversized?
Is my assumption correct that the higher lower modulation limit is a disadvantage for us?
How would you approach this situation? How serious do you see the issue, and what options do I have?
Thanks for your help
HilfeHilfe schrieb:
Uff Always those clever posts that don’t help anyone, except that the poster ends up with one more pointless comment.....
If it were spoken, people would say: As long as the air made a noise.....
I would first talk to your energy consultant. You usually have one for gas as well, to check if it’s really a problem. But yes, I also think it’s significantly oversized....
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